The Cardiovascular Effects of Air Pollution: the Role of Nitric Oxide

October 8, 2009 updated by: University of Edinburgh
Exposure to air pollution has been linked to increased cardiorespiratory morbidity and mortality. The exact component of air pollution that mediates this effect is unknown, but the link is strongest for fine combustion derived particulate matter derived from traffic sources. Recently, it has been demonstrated that inhalation of diesel exhaust impairs vascular vasomotor tone and endogenous fibrinolysis. The mechanism underlying these detrimental vascular is unclear, but is thought to be via oxidative stress and altered bioavailability of endogenous nitric oxide. In these studies we plan to elucidate the role of endogenous nitric oxide (NO) in the adverse vascular responses observed following exposure to diesel exhaust.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Anticipated)

16

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Sweden
      • Umeå, Sweden
        • Umeå University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 40 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy volunteers

Exclusion Criteria:

  • Use of regular medication (except oral contraceptive pill)
  • Current smokers
  • Significant occupational exposure to air pollution
  • Intercurrent illness

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Diesel Exposure
1 hour exposure to dilute diesel exhaust at a concentration of 300 µg/m3 with intermittent exercise
Procedure: Forearm Vascular Study
Forearm venous occlusion plethysmography during intraarterial infusion of L-NMMA (2-8 µmol/min) followed by co-infusion of sodium nitroprusside (90-900 ng/min) as a "nitric oxide clamp". Forearm blood flow then measured during the clamp in response to infused vasodilators acetylcholine (5-20 mg/min), bradykinin (100-1000 pmol/min), verapamil (10-100 µg/min) and sodium nitroprusside (2-8 µg/min).
Other Names:
  • BK
  • SNP
  • ACh
Experimental: Air Exposure
1 hour exposure to filtered air during intermittent exercise
Procedure: Forearm Vascular Study
Forearm venous occlusion plethysmography during intraarterial infusion of L-NMMA (2-8 µmol/min) followed by co-infusion of sodium nitroprusside (90-900 ng/min) as a "nitric oxide clamp". Forearm blood flow then measured during the clamp in response to infused vasodilators acetylcholine (5-20 mg/min), bradykinin (100-1000 pmol/min), verapamil (10-100 µg/min) and sodium nitroprusside (2-8 µg/min).
Other Names:
  • BK
  • SNP
  • ACh

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Forearm blood flow as measured by venous occlusion plethysmography during infusion of NOS inhibitors and vasodilators
Time Frame: 2-4 hours after exposure
2-4 hours after exposure

Secondary Outcome Measures

Outcome Measure
Time Frame
Plasma nitrite concentrations
Time Frame: During forearm study
During forearm study
Plasma concentrations of t-PA and PAI
Time Frame: After infusion of bradykinin during forearm study
After infusion of bradykinin during forearm study

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Edinburgh

Collaborators

Umeå University

Investigators

  • Principal Investigator: Anders Blomberg, MD PhD, Umeå University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2009

Primary Completion (Actual)

July 1, 2009

Study Completion (Actual)

July 1, 2009

Study Registration Dates

First Submitted

February 17, 2009

First Submitted That Met QC Criteria

February 17, 2009

First Posted (Estimate)

February 18, 2009

Study Record Updates

Last Update Posted (Estimate)

October 9, 2009

Last Update Submitted That Met QC Criteria

October 8, 2009

Last Verified

October 1, 2009

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • DNR 08-185M/1

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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